I don't believe this.
But it's true, regardless if you believe it or not.
I know Prepare3d has not solved OOM problem.
No, it hasn't, but it's FAR more stable, and it looks so much better too. And it uses modern video cards much better (it uses DirectX 11 ) so, the better your video card is, the better P3D performs. Upgrading the video card is quite easy, and the new cards which just came out from nVidia offers a large performance bonus, with reasonable prices.
FSX, on the contrary, doesn't run so much better with a better video card, because you are stuck to choose between the outdated and memory-consuming DX9 and a very bugged DX10 implementation. And FSX is WAY more crash-prone, especially when graphic is concerned, and this will only get worse, since nobody is going to fix bug in video driver that only happens with DX9 apps.